Refrigeration systems such as those used in automotive and home appliances and air conditioners require that the refrigerant used be relatively free of foreign matter such as oil, water, and air. Since these systems rely on pressure to keep the refrigerant compressed, it is critical that hermetic integrity be maintained. If the refrigeration system breaks down, the refrigerant must be removed to facilitate the repair of the system. In the past, the refrigerant, a colorless, odorless gas, was discharged into the atmosphere. This discharge not only wasted the relatively expensive refrigerant, but also may have contributed significantly to the breakdown of the ozone layer of the earth's atmosphere. Because fluorocarbons used in automotive and household appliances are environmentally dangerous, it is desirable to prevent their harmful release.
Recycling capabilities provide a financial benefit for technicians who generally filter and reuse refrigerant instead of replacing it with relatively costly new refrigerants. Containment and recycling is also economically beneficial to the technician who recovers the refrigerant from refrigeration units which are beyond repair.
Unfortunately, the environmental and economic advantages of recycling refrigerant must compete with the temptation of simply releasing the refrigerant into the atmosphere. In light of this conflict, any successful recover or recycling system must provide repair personnel with an easy to use apparatus that encourages the recycling of the refrigerant in comparison to the easier course of merely releasing the refrigerant into the atmosphere.
Refrigerant recovery processes taught in the Prior Art have focused on the use of molecular sieves and silica gels, products which are expensive to purchase, and while re-usable, require the application of heat during the regeneration process. This step of heating adds significant costs to the economics of the process, and often adds to the temptation to simply discard the molecular sieves or silica gel, with associated appropriate environmental disposal concerns.
Venturi devices have found application in fluidized bed food freezers in which the refrigerant is turbo expanded air, and in which the refrigerant is circulated by a venturi-like device such as an ejector as patented in U.S. Pat. No. 5,438,845. Variable volume venturi devices have also been described as air induction inputs for air conditioning system. Each unit in this configuration was described as including a round inlet collar, an elongated plenum to form a venturi, hinged volume dampers, secondary air openings, bottom plenum chamber and a pattern controller and patented in U.S. Pat. No. 4,448,111.
More traditional uses of a venturi reside in the gas scrubber field, when used to remove particulate matter from a gaseous effluent stream, as for example in the following United States Patents: U.S. Pat. No. 5,279,646, U.S. Pat. No. 4,140,501; U.S. Pat. No. 4,057,602; U.S. Pat. No. 4,012,469; U.S. Pat. No. 3,998,612; U.S. Pat. No. 3,898,308; U.S. Pat. No. 3,690,044; U.S. Pat. No. 3,638,924; and U.S. Pat. No. 3,616,613.
To date, there still exists a need for a cost-effective technology which can purify gas streams, particularly refrigerants, which contain water vapor or oil contaminants or both, which capitalizes on venturi design, yet which is easy to operate without the need for heat-intensive regeneration procedures.